Heat-conducting fins for bus bars and other electrical conductors

ABSTRACT

A plurality of heat-conducting fins disposed on various types of electrical conductors both insulated and uninsulated, and for both high- and low-voltage applications such as in bus bars, disconnect and knife switches, and circuit breakers. Each of said fins includes a central opening which is slightly smaller in one dimension than the conductor on which the fins are assembled and therefore must be distorted somewhat during assembly on the conductor. The distortion in each fin develops a torsional stress in the fin which causes it to tightly grasp the conductor. In certain high-voltage applications, the fin may be insulated or bent over to reduce the effective radial size of the fins in the overall conductor assembly without reducing its surface area and ability to convect heat.

United States Patent [72] inventor Charles M. Cleaveland Monroeville,Pa.

[21 Appl. No. 4,493

[22] Filed Jan. 21,1970

[45] Patented Nov. 16, 1971 [73] Assignee Westinghouse ElectricCorporation Pittsburgh, Pa.

[ 54] HEAT-CONDUCTING FINS FOR BUS BARS AND OTHER ELECTRICAL CONDUCTORS11 Claims, 19 Drawing Figs. [52] US. Cl l74/l5, 174/16, 174/28, 174/99 B[51] Int. Cl 1101b 7/34 [50] Field oiSearch 165/185,

181,182; 174/15 L, 16, 168, 28,29, 99 B, 12 7 HS Primary Examiner- LewisH. Myers Assistant Examiner-A. T. Grimley Allorneyiv-A T. Stratton andClement L. McHale ABSTRACT: A plurality of heat-conducting fins disposedon various types of electrical conductors both insulated anduninsulated, and for both highand low-voltage applications such as inbus bars, disconnect and knife switches, and circuit breakers. Each ofsaid fins includes a central opening which is slightly smaller in onedimension than the conductor on which the fins are assembled andtherefore must be distorted somewhat during assembly on the conductor.The distortion in each fin develops a torsional stress in the fin whichcauses it to tightly grasp the conductor. in certain high-voltageapplications, the fin may be insulated or bent over to reduce the effective radial size of the fins in the overall conductor assemblywithout reducing its surface area and ability to convect heat.

PATENTEflNnv 16 I97! 3'. 621 .108

SHEET 1 [IF 3 FIG.| 34

WITNESSES INVENTOR mun .fia uau Charles M. Cleovelond (M 2 0m, Llaio/ATTORNEY HEAT-CONDUCTING FINS FOR BUS BARS AND OTHER ELECTRICALCONDUCTORS BACKGROUND OF THE INVENTION This invention relates generallyto cooling fins on electrical conductors and more specifically tocooling fins on bus bars and other types of electrical conductors.

It is usually desirable to use as little material as possible in anelectrical conductor to carry a given magnitude of electrical current.Bus bars and other types of electrical conductors which carry relativelylarge amounts of current at either low or high voltage must normally bedesigned with a certain minimal cross-sectional area for two reasons:(I) To minimize electrical resistance which, if too high, will causeinefficient transfer of electric power along the conductor and (2) tominimize the temperature of a conductor for a given current carried bythe conductor. In certain applications, the limiting or controllingfactor in reducing the size of a conductor is not the electricalresistance but rather the thermal aspect. Problems, such as melting ofinsulation, often outweigh the voltage drop due to the increasedresistance when the crosssectional area of a conductor is reduced for agiven amount of current. The size of the bus bars or electricalconductors, therefore, has been designed primarily with the aim ofkeeping the temperature down rather then providing less resistance tothe flow of electrical current. Various means have been proposed toreduce the required size of bus bars and electrical conductors whilestill maintaining the proper heat-dissipating ability, but such meansare usually expensive and complicated. An example of such a means isforced air convection in the vicinity of the bus bar and or forced airconvection in the vicinity of the bus bar or forced air convection in abus duct in which bus bars are mounted. Another means proposed is theuse of fins to dissipate the heat, such as disclosed in US. Pat. No.3,067,279 issued to B. P. Baker on Dec. 4, 1962 and assigned to the sameassignee. But to be elfective fins must be tightly secured to orretained on the associated conductor in a reliable manner; and must lendthemselves to easy assembly and must be safe. In high-voltageapplications, fins must so designed as to prevent corona or arcingbetween adjacent conductors and between such conductors and ground. Itis therefore desirable to provide an improved construction forelectrical conductors having fins mounted thereon which providesadvantages over known constructions with respect to the latterrequirements.

SUMMARY OF THE INVENTION In accordance with the invention, bus bars andother types of electrical conductors whether insulated or uninsulated,to carry a given amount of current, are reduced in size without anobjectionable increase in electrical resistance and include means fordissipating the heat which generates in the conductor especially inhigh-current applications. The latter means comprises fins which aremounted on the bus bar to add more surface area to the bus bar andaccordingly to allow more heat to escape into the surroundingatmosphere. Such fins are not glued or welded on but are retained intheir assembled positions on the associated electrical conductor in arigid manner due to their unique structure. Regardless of the shape ofthe conductor, which may be round, rectangular or any other shape, thefins are made slightly smaller in one dimension along the insideperimeter where each fin fits over the associated conductor. Thus whenthe fin is assembled onto the conductor it must be twisted and distortedin order to fit. In so doing it sets up a counteracting torsional stresstending to grasp the conductor to which it is secured or attachedtenaciously. This construction provides for a better joint between theconductor which is building up heat and the bodies or fins which aremounted thereon to assist in removing it. Since it has been found thatfor the usual types of electrical insulation and for the normalthicknesses of such insulation, there is a radial temperature gradientacross the insulation of only 9 or 10 for a 65 gradient between the airand the bus, applying fins to insulated electrical conductors operatesquite efficiently for removing heat from the insulated conductor. Thisof course is very important for high-voltage heat removal. It is alsopossible to mount the fins directly to the conductor and then insulatethe entire assembly. In accordance with this em bodiment of theinvention, an insulating precoating is applied to each fin. The fin isthen mounted on the conductor and the entire assembly is immersed into afluidized epoxy coating bath to provide electrical insulation over theentire combination. This method is particularly useful for high-voltageapplications. It has also been found that in very high-voltageembodiments of the inventions, the sharp outer edges of the fins may beserrated and rolled over providing a radiused edge and providing thesame surface area in each fin but reducing the electrical stress at theouter edge of the fin. Finally, it has been found in certain embodimentsthat the heat transfer between the bus bar and the fins can be improvedby serrating the inner perimeters of the fins and rolling the serratedsections creating curved tabular surfaces which will provide increasedcontact area with the conductor.

It is therefore an object of this invention to provide an improved meansto attach fins to electrical conductors.

It is also an object of the invention to remove heat economically from ahigh-voltage electrical conductor without causing corona or arcing.

It is a further object to provide an improved means for removing heatfrom a conductor where both the conductor and its heat-removing meansare both electrically insulated.

A still further object of the invention is to provide an electri' calconductor having fins thereon which is adapted to be mounted in a busduct, on a switch, or on a circuit interrupter.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects of the invention will beapparent from the following detailed description taken in conjunctionwith the accompanying drawings in which:

FIG. I is an electrical conductor section with fins mounted on it;

FIG. IA is a sectional view through the conductor and fins in FIG. 1which diagrammatically shows the effect of the torsion within the tinwhen slipped onto the conductor;

FIG. 2 is a side view of an individual fin from FIG. 1 but in itsunmounted and untorsioned condition;

FIG. 3 is a view of a fin with a serrated and rolled inner perimeter;

FIG. 4 is a sectional view of FIG. I with fins of the type shown in FIG.3 mounted with the rolled tabular edges contacting the bus bar;

FIG. 5 is a view of a modified fin construction with both inner andouter perimeters serrated and rolled;

FIG. 6 is a sectional view of an electrical conductor having finsmounted thereon of the type shown in FIG. 5;

FIG. 7 is a front elevational view of a circular fin construction;

FIG. 8 is a view of a circular electrical conductor section, solid ortubular, having fins mounted thereon of the type shown in FIG. 7 similarto the mounting shown in FIG. 1;

FIG. 9 is a view of a plurality of axially spaced groups of fins similarto the fin shown in FIG. I mounted on an electrical conductor sectionand inclosed in bus duct. The details of the characteristic bends in thefins shown in FIG. I are omitted from this view for the sake of clarity;

FIG. 9A is a view of a fin with a rolled and serrated outer edge and aplain inner edge;

FIG. 10 is a view similar to FIG. 9 in which the fins of a group of finsmounted near the end of an electrical conductor section are graduallyreduced in size;

FIG. 11 is a view of groups of fins mounted on an electrical conductorsection with the fins assembled over electrical insulation which isprovided on the conductor;

FIG. 12 is a view of fins similar to those shown in FIG. 3, precoatedand mounted on bare or uninsulated conductor and the entire sectioncoated with an insulating material so as to insulate the fins andconductor as a unit;

FIG. 13 is a top view of fins mounted on an electrical conductor whichforms part of a knife switch assembly;

FIG. 14 is a side view of fins mounted on an electrical conductor whichforms part of a knife switch assembly;

FIG. 15 is a view of fins mounted on an electrical conductor which formspart of a circuit breaker section;

FIG. 15A is a view of the fin 17 on the electrical conductor 74 ofFIG.11S; and

FIG. 16 is a view of fins mounted on a round electrical conductor whichforms part of a circuit breaker section used in conjunction with avacuum-type circuit interrupter.

DESCRIPTION OF THE PREFERRED EMBODIMENTS S Referring to the drawings andin particular to FIG. 1, a section of electrical conductor or bus barstructure 20 comprising both an elongated electrical conductor or busbar section 22 and heat-exchanging or heat-dissipating means 24 isshown. The electrical conductor section 22 is composed of an electricalconductor such as copper or aluminum, which may be generally solid ortubular with or without electrical insulation as desired. Theheat-exchanging means 24 is composed of a plurality of axially spacedprotrusions or fins 26. Referring to FIG. 2 each protrusion 26 is astamped sheet primarily aluminum fin. Each fin 26 has an inner perimeter28 and an outer perimeter 30 which is generally oval in shape. Referringagain to FIG. 1 for one embodiment of the invention, the electricalconductor section 22 is a section of generally rectangular aluminum oraluminum-based alloy metallic bus bar without insulation. As can be seenthe inner perimeter 28 of the fin 26 is tapered inwardly as indicated at32. Although the opening 34 of the inner perimeter 28 is generally theshape of the rectangular bus bar 22, because of the taper indicated at32, at least one dimension of the inner perimeter 28 of the fin 26before assembly on the electrical conductor section 22 is less than thecorresponding dimension of the electrical conductor section 22 and thefin 26 will not fit properly unless the fin 26 is forced open ordeformed to allow it to slide onto the bus bar section 22. When thishappens, the main body of fin 26 distorts in such a manner that innerperimeter 28 bows or bends generally in one direction 90 while outerperimeter 30 bows or bends generally in the opposite direction 92.Referring to FIG. 1A, the stress caused by the opposed bowing of thefins perimeters creates a torsional force 94 to be set up by surface 36of fin 26 causing the inner perimeter or central opening 28 in thevicinity of taper 32 to grasp bus bar 22. As this happens fin 26 becomesfirmly affixed or secured to bus bar 22 and the joint or contact betweenthe bus bar 22 and each of the fins 26 is of such a nature that the fins26 provide an efficient heat sink for the heat generated in bus bar 22.This is so because at least one dimension of the fin 26 is smaller thanthe electrical conductor onto which it is mounted.

Referring now to FIG. 3, there is illustrated another embodiment of theinvention. This embodiment shows a flexible metallic fin 26 havingserrations 38 placed along the inner perimeter 28 of fin 26'. Theseserrations 38 are rolled to form a contact surface tab 40 along theinner perimeter 28. As shown in FIG. 4, the rolled edge or tab 40provides more con tact surface area between the fin 26 and the bus bar22. For reasons of clarity and simplicity, the main body of fin 26' asshown in FIG. 4 does not reflect the distortion that is present in thefin. Nevertheless the distortion is present to as great an extent asshown in FIG. 1. The only purpose of the serrations is to allow the finwhich has a rolled edge to still be flexible enough to torsion and gripthe bus bar as efiectively as the fin showing in F IG. 2 without therolled edge.

Referring to FIG. 5, there is illustrated a third embodiment of theinvention fin 26". Fin 26" includes a rolled edge and serrations 38along the inner perimeter 28 forming tabs or edges 40 and alsoserrations 42 along outer perimeter 30 forming tabs or edges 44 on theouter perimeter. When this particular embodiment of fin is mounted onbus bar 22 as shown in FIG. 6, both the rolled inner tabs 40 and outertabs 44 come into play. The inner tabs 40 grasp or engage conductor 22in a manner similar to that shown in FIG. 4, and the outer tabs 44 arebent over to reduce the corona resulting from the sharp edges ofperimeter 30, as shown in FIG. 1. This is particularly desirable inhigh-voltage applications. Again the main body of fin 26 is not shown inits true distorted form for reasons of simplicity but in fact it assumesnearly the same shape and applies the same relative forces as shown inFIGS. 1 and 1A respectively.

Referring to FIG. 7, there is shown an alternative fin 27 for use ongenerally circular cylindrical solid or tabular conductors and in thiscase, the fin 27 has a circular outer perimeter 31 and an oval innerperimeter 29. FIG. 8 shows a view of a section of an electricalconductor or bus bar structure 20' comprising a section of circularcylindrical electrical conductor 21 and heat-exchanging means 124. Saidheat-exchanging means 124 comprises a plurality of axially spaced fins27. As is shown in FIG. 7, inner perimeter or central opening 29 of fin27 is oval shaped and narrower in the vicinity of 33. This correspondsto the taper 32 on inner perimeter 28 of fin 26 as shown in FIG. 2. Asis shown in FIG. 8, fin 27 distorts its shape when mounted on electricalconductor section 21 in a manner similar to the way fin 26 distorts whenmounted on electrical conductor section 22 as illustrated in FIG. 1,inner perimeter 29 bows or bends slightly generally in one direction andthe outer perimeter 31 bows or bends generally in the opposite direction192. Again as in the case of fins 26 mounted on conductor 22, the effectof the bowing is to introduce a force into each of the fins 27 in thevicinity of 33 causing each fin 27 to rigidly adhere to or be retainedon the electrical conductor section 21. Although not shown, fin 27 canhave alternate or modified construction with combinations of inner andouter rolled and serrated perimeters 29 and 31 respectively which aresimilar to the rolled edges and serrations on fin 26 shown in FIGS. 3and 5. The purposes for such rolls and serrations are the same asdescribed in conjunction with the fins 26' and 26" shown in FIGS. 4 and6 respectively, namely more fin surface area in contact with the bus bar21 and/or a bending over of outer perimeter 31 for higher voltageapplications. It should be noted at this point that, as illustrated inFIG. 9A with respect to both fins 26 and 27 another embodiment of theinvention, namely fin 26" exists. It has no inner roll and serrationsand thus no inner tabs on inner perimeter 28 but has outer rolled edgesand serrations 42 and outer tabs 44 along the outer perimeter 30. Thisapplies in the case where the high-voltage problem is severe enough toforce a bending over of the fin edge 30 and yet the gripping power ofthe distorted fin is sufficient or adequate and/or the heat generated inthe bus bar is of low enough magnitude not to justify the extra surfacearea provided by inner tabs.

Referring to FIG. 9 there is shown a series or plurality of axiallyspaced heat-exchanging means 24, on an electrical conductor section 22.The electrical conductor section 22 may be of any shape and may beelectrically insulated or uninsulated depending upon the particularapplication. For purposes of simplicity assume it is the embodiment of abus bar as discussed previously in dealing with FIGS. 1, 2, 3, 4, 5, and6. The heat-exchanging means 24 are axially spaced and mounted inmultiple series over the length of the bus bar 22 to assist in theremoval of heat from said bus bar. It will be noted that certain areasof bus bar 22, namely the areas 46 have no fins. This is so because theefficiency of a section of heatexchanging means 24 is usually of such amagnitude with respect to the removal of heat from bus bar 22 thatheatexchanging means 24 need not be included along every part of bus bar22 but only in clusters at axially spaced locations. This allows spaceand electrical clearance for bus supports or ventilation or both.Naturally, the temperature in the vicinity of the heat exchangers 24will be slightly lower than that in the vicinity of sections 46 whichhave no heat exchangers but a profile plot of the temperature versuslength of this configuration is not appreciably different from theprofile plot resulting from the same number of fins being mounted atconstant equal axially spaced or discrete distances along the entirelength of bus bar 22. If necessary the entire bus bar section 22 withheat exchange means 24 may be mounted within enclosure 100. Enclosure100 may be a metal bus duct or may be the housing section for metal-cladswitchgear. In either case, the enclosure may be so constructed as toenclose multiple runs of the bus bars. FIG. shows a variation of theconstruction shown in FIG. 9 in that a section of heat-exchanging means24 composed of fins 26a through 26c is mounted near the end 18 of busbar 22. The difference in this case is that the fins 26a through 26c ofthe heat exchanger or dissipation means 24 are of the same general shapebut of difl erent or gradually reduced sizes. It should also be realizedthat heat exchanger means 24' may be comprised of more or less than fivefins. This particular variation of heat exchanger means 24 is used toreduce electrical stress where the group of fins terminate. This is ofvalue where very high voltages are used.

FlG. 11 shows a section of electrical conductor construction 120 whereinthe conductor section 121 comprises a conductor 23 and insulation 19. Inthis case the fins are mounted on insulation 19 rather than directly onconductor 23 but because of the low change in temperature across theinsulation the heat exchanger means 124 operates quite efiiciently.Again fins 27 are not shown in their actual distorted state but aremerely shown as vertical sections for reasons of clarity and simplicity.

FIG. 12 shows a section of electrical conductor structure 220 with heatexchanger means 224 and bus bar section 210. Fins 260 are fashioned in amanner similar to that of the embodiment shown in FIG. 3 with rolled andserrated inner perimeter 128 forming tabs or edges 140. In this caseeach fin 260 is precoated with an electrical insulation that conductsheat relatively well, such as high-density polyethylene or polypropyleneinsulation 52. The presence of the high-density polyethylene orpolypropylene insulation 52 has the effect of lessening theheat-dissipating ability of fin 260 but is necessary in order to coatthe fin with epoxy 290 by the fluidized bed coat process. Were theprecoat 52 not present, the fins 260 would not have enough insulationsince the fluidizing process will not coat with same thickness on thethin surface as on the bus bar surface. In general the precoated fins260 and the conductor 210 on which they are mounted are immersed as aunit in the floating epoxy material and coated with the insulatingmaterial as a unit. The result is a uniformly insulated finned conductorsection 220 for use in high-voltage application. At lower voltages, theprecoat can be omitted and the difi'erence in insulation thicknessbetween the fins and the bus bar can be tolerated.

FIGS. 13 and 14 show another embodiment of the inven tion. FIGS 14 and13 show a section of heat-exchanging means 24 with fins 26 mounted on anelectrical conductor which forms the blade section 56 of a pivotallymounted knife switch 48. The knife switch is shown with the insulatingbases or insulators 54 on one end supporting a conductor 58 which, inturn, supports the pivot-supporting means 60 onto which is mountedblades 56 with heat-exchanging means 24. The blades 56 in the closedposition engages the contact jaw 62 which is supported by the otherinsulator 54. The blades 56 rotate about pivot 60 and engage the contactjaw 62 when the knife switch is closed. The view in FIG. 13 showsseparate fins for each blade 56 thereby allowing flexing between theblades. The heat-exchanging means 24 on knife switch 48 illustrates theapplication of the invention to similar types of equipment such asoutdoor disconnect switches of the type described in US. Pat. No.3,079,474 dated Feb. 26, 1963 covering an invention disclosed by E. F.Beach et al. and assigned to the same assignee as the present invention.That invention shows a single tubular conductor onto which fins can bemounted for heat removal.

FIG. 15 shows a side view of another embodiment of the invention withthe heat-exchanging means 24 employed in conjunction with a circuitbreaker assembly 95. The circuit interrupter means of assembly can be ofany general type. One type is described in detail in a copendingapplication. Ser. No. 657,122 filed on July 31, 1967 by R. Frink andassigned to the same assignee as this invention. In this case theappropriate circuit interrupting means 85 is mounted within an enclosingmeans or housing 97, said circuit-interrupting means may be a vacuum,oil or sulfurhexafloride interrupter. An operating mechanism 83 and apair of interrupting contacts are generally shown by 81A and 818. Thecircuit interrupting means 85 is connected by means of conductors 80 tothe upper and lower U-shaped conductors 96 and 98. Both the conductors96 and 98 are supported by standoff insulators 93 on one side and areconnected to the output conductors 70 on the other. The top U-shapedconductor 96 supports a circular cylindrical conductor 74 on which ismounted a finned heatexchanging means 24 such as any of heat-exchangingmeans previously described. Conductor 74 may be an extension of topoutput conductor 70. In one embodiment, fin 17 as shown in FIG. 15Awhich comprises the heat-exchanging means 24 is similar to fins 26 and27 which have been already described. Each fin 17 in this case isgenerally rectangular on the outer perimeter 300 similarly to fin 26,but oval on the inner perimeter 330 similarly to fin 27. All themodifications previously described for use with either fin 26 or 27 maybe also applied with fin 17. Generally, circuit breaker 95 operates byproviding a current path between the two output conductors 70 in serieswith the interrupting means 82 and the finned conductor 74 as well asthe U-shaped conductors 96 and 98.

FIG. 16 shows another embodiment of the invention. FIG. 16 is a partialview of a vacuum circuit interrupter 79 with a heat-exchanging means 24mounted on an electrical conductor 80 between the vacuum interrupter 76and the output terminal 81 and rigidly supported by supporting means orinsulator 77. In this case alternating electrical current flows betweenthe terminal 81 and vacuum interrupter 76. In area 78 of conductor 80,the heat-exchanging means 24 is placed to dissipate heat which resultsfrom electrical current flowing through circuit interrupter 79 whenclosed.

The apparatus embodying the teachings of the inventor has severaladvantages, for example, the fins can be easily installed and maintaintheir position on the various conductors without the use of any kind ofsecuring hardware, the fins enable the conductor to dissipate heat moreefficiently than if a mere bare conductor were used and thus allow forthe use of either a small conductor carrying the same amount of currentor for a conductor of the same size carrying more current. The fins canbe used to remove heat from conductors carrying high voltage by a numberof variations, namely either bending the outer edges of the fin over soas to reduce the electrical stresses at the outer edge of the fin or bycoating the entire fin and conductor within an insulating material or byinsulating the conductor and then installing the fins. In addition sincethe heat-exchanging means are constructed of a multitude of singularfins, should one or several fins be bent, broken or otherwise rendereduseless others can easily replace them whereas for example, if the heatexchanger were cast aluminum the entire assembly would have to bereplaced.

It is to be understood that in certain applications the finnedconductors may be placed inside of bus ducts or metal-clad switchgear ofeither singular or multiple phase. It is also to be understood that thefins may seat themselves in slightly different positions with respect toeach other upon any given conductor without affecting the coolingfunction of the fins.

Since numerous changes may be made in the abovedescribed apparatus anddifferent embodiments of the invention may be made without departingfrom the spirit and scope thereof, it is intended that all mattercontained in foregoing description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. An electrical conductor section comprising a main body of electricalconductor extending between the ends thereof,

heat-exchanging means mounted on said main body of electrical conductor,said heat-exchanging means comprising a plurality of flexible metallicprotrusions spaced axially along the length of said electrical conductorsection, each of said metallic protrusions having material removed fromwithin its outer perimeter to form a central opening spaced from saidouter perimeter, said opening facilitating the assembly of saidprotrusion on said main body of electrical conductor, said opening beinggenerally the same shape as said main body of electrical conductor onwhich each of said protrusions is to be mounted by slightly smaller inat least one dimension thereby causing each said protrusion to bedistorted when assembled on said main body, the torsion in each of saidprotrusions resulting from such distortion and the flexibility of eachof said metallic protrusions maintaining holding pressure on theassociated main body of electrical conductor.

2. An electrical conductor section with heat-exchanging means accordingto claim 1 wherein the electrical conductor is a generally rectangularmetallic bus bar, said electrical conductor section being adapted to bemounted in a metal enclosure and each protrusion is in the shape of afin with each said fin being generally the same size and shape.

3. An electrical conductor section with heat-exchanging means accordingto claim 2 wherein both said metallic bus bars and fins are electricallyuninsulated.

4. An electrical conductor section with heat-exchanging means accordingto claim 1 wherein each protrusion is in the shape of a fin, said mainbody of electrical conductor is generally circular cylindrical in shapeand each said fin has an oval shaped inner perimeter for mounting onsaid generally circular cylindrical electrical conductor.

5. An electrical conductor section comprising a main body of electricalconductor extending between the ends thereof, heat-exchanging meansmounted on said main body of electrical conductor, said heat-exchangingmeans comprising a plurality of generally stamped primarily aluminumsheet metal fins spaced axially along the length of said main body ofelectrical conductor, each of said fins having material removed fromwithin its outer perimeter forming an opening, the inner perimeter ofeach fin surrounding said opening being serrated and rolled, said rolledinner perimeter of each of said fins providing holding pressure over arelatively larger area of said main body of electrical conductor.

6. The combination as claimed in claim 5 wherein the outer perimeter ofeach said fin is rolled to thereby reduce the effective radial size ofthe fin to prevent arcing to adjacent conductors and serrated to allowtorsioning of the fin.

7. An electrical conductor section comprising a main body of electricalconductor extending between the ends of said conductor section,heat-exchanging means mounted on said main body of electrical conductor,said heat-exchanging means comprising a plurality of generally stampedprimarily aluminum sheet metal fins, each of said fins having materialremoved from within its outer perimeter forming an opening, the outerperimeter of each of said fins being rolled and serrated to reduce theeffective radial size of each fin.

8. An electrical conductor section comprising a main body of electricalconductor intermediate the ends thereof, heatexchanging means mounted onsaid main body of electrical conductor, said heat-exchanging meansinteracting with said main body of electrical conductor and thesurrounding environment to increase the transfer of heat from said mainbody of electrical conductor, said heat-exchanging means comprising aplurality of primarily aluminum metallic protrusions axially spacedalong the length of said main body of electrical conductor, each of saidpriman'ly aluminum bodies being formed in the shape ofa fin fromflexible primarily aluminum sheet, each of said fins having materialremoved within its outer perimeter to form a central opening, saidopening facilitating the assembly of said fin on said main body ofelectrical conductor, said opening being generally the same shape assaid main body of electrical conductor on which each fin is to bemounted but slightly smaller in at least one dimension thereby causingthe fin to be distorted when assembled, the

torsion in each of said fins resulting from said distortion and theinherent flexibility of the fins maintaining holding pressure on saidmain body of electrical conductor, said electrical conductor sectionbeing adapted to be mounted in a metal enclosure with each of said finsbeing generally the same size and shape, said main body of electricalconductor comprising an electrical conductor and electrically insulatingmeans surrounding said main body of electrical conductor, only said finsbeing electrically uninsulated.

9. An electrical conductor section with heat-exchanging means accordingto claim 8 wherein said fins are also being electrically insulated by aninsulating means.

10. The combination as claimed in claim 8, wherein said main body ofelectrical conductor comprises a generally rectangular metallic bus bar.

11. A combination of insulated metallic electrical conductor section andheat-exchanging means, said heat-exchanging means comprising nonmagneticmetallic fins in physical contact with said electrical conductor, saidfins being precoated with an electric insulating material, thecombination of said precoated fins and said electrical conductor beingcoated by the fluidized bed coating method with a layer of insulatingmaterial such as epoxy resin.

1. An electrical conductor section comprising a main body of electricalconductor extending between the ends thereof, heatexchanging meansmounted on said main body of electrical conductor, said heat-exchangingmeans comprising a plurality of flexible metallic protrusions spacedaxially along the length of said electrical conductor section, each ofsaid metallic protrusions having material removed from within its outerperimeter to form a central opening spaced from said outer perimeter,said opening facilitating the assembly of said protrusion on said mainbody of electrical conductor, said opening being generally the sameshape as said main body of electrical conductor on which each of saidprotrusions is to be mounted but slightly smaller in at least onedimension thereby causing each said protrusion to be distorted whenassembled on said main body, the torsion in each of said protrusionsresulting from such distortion and the flexibility of each of saidmetallic protrusions maintaining holding presSure on the associated mainbody of electrical conductor.
 2. An electrical conductor section withheat-exchanging means according to claim 1 wherein the electricalconductor is a generally rectangular metallic bus bar, said electricalconductor section being adapted to be mounted in a metal enclosure andeach protrusion is in the shape of a fin with each said fin beinggenerally the same size and shape.
 3. An electrical conductor sectionwith heat-exchanging means according to claim 2 wherein both saidmetallic bus bars and fins are electrically uninsulated.
 4. Anelectrical conductor section with heat-exchanging means according toclaim 1 wherein each protrusion is in the shape of a fin, said main bodyof electrical conductor is generally circular cylindrical in shape andeach said fin has an oval shaped inner perimeter for mounting on saidgenerally circular cylindrical electrical conductor.
 5. An electricalconductor section comprising a main body of electrical conductorextending between the ends thereof, heat-exchanging means mounted onsaid main body of electrical conductor, said heat-exchanging meanscomprising a plurality of generally stamped primarily aluminum sheetmetal fins spaced axially along the length of said main body ofelectrical conductor, each of said fins having material removed fromwithin its outer perimeter forming an opening, the inner perimeter ofeach fin surrounding said opening being serrated and rolled, said rolledinner perimeter of each of said fins providing holding pressure over arelatively larger area of said main body of electrical conductor.
 6. Thecombination as claimed in claim 5 wherein the outer perimeter of eachsaid fin is rolled to thereby reduce the effective radial size of thefin to prevent arcing to adjacent conductors and serrated to allowtorsioning of the fin.
 7. An electrical conductor section comprising amain body of electrical conductor extending between the ends of saidconductor section, heat-exchanging means mounted on said main body ofelectrical conductor, said heat-exchanging means comprising a pluralityof generally stamped primarily aluminum sheet metal fins, each of saidfins having material removed from within its outer perimeter forming anopening, the outer perimeter of each of said fins being rolled andserrated to reduce the effective radial size of each fin.
 8. Anelectrical conductor section comprising a main body of electricalconductor intermediate the ends thereof, heat-exchanging means mountedon said main body of electrical conductor, said heat-exchanging meansinteracting with said main body of electrical conductor and thesurrounding environment to increase the transfer of heat from said mainbody of electrical conductor, said heat-exchanging means comprising aplurality of primarily aluminum metallic protrusions axially spacedalong the length of said main body of electrical conductor, each of saidprimarily aluminum bodies being formed in the shape of a fin fromflexible primarily aluminum sheet, each of said fins having materialremoved within its outer perimeter to form a central opening, saidopening facilitating the assembly of said fin on said main body ofelectrical conductor, said opening being generally the same shape assaid main body of electrical conductor on which each fin is to bemounted but slightly smaller in at least one dimension thereby causingthe fin to be distorted when assembled, the torsion in each of said finsresulting from said distortion and the inherent flexibility of the finsmaintaining holding pressure on said main body of electrical conductor,said electrical conductor section being adapted to be mounted in a metalenclosure with each of said fins being generally the same size andshape, said main body of electrical conductor comprising an electricalconductor and electrically insulating means surrounding said main bodyof electrical conductor, only said fins being electrically uninsulated.9. An electrical conductor section with heat-exchanging means accordingto claim 8 wherein said fins are also being electrically insulated by aninsulating means.
 10. The combination as claimed in claim 10, whereinsaid main body of electrical conductor comprises a generally rectangularmetallic bus bar.
 11. A combination of insulated metallic electricalconductor section and heat-exchanging means, said heat-exchanging meanscomprising nonmagnetic metallic fins in physical contact with saidelectrical conductor, said fins being precoated with an electricinsulating material, the combination of said precoated fins and saidelectrical conductor being coated by the fluidized bed coating methodwith a layer of insulating material such as epoxy resin.